Method of forging gear worms



Nov. 20, 1923.. 7 1,474,516

A. L. EICHER Filed Aug. 21, 1920 5 Sheets-Sheet 1 Nov. 20 1923. 1,474,516

L. EICHER METHOD OF FORGING GEAR WORMS Filed Aug. 21. 1920 s Sheets-Sheet 2 W'QMc WMQW Nov. 20 1923. 1,474,516

Y A. L. EICHER METHOD OF FORGING GEAR WORMS Filed Aug. 21 1920 5 Sheets-Sheet 5 AL. EM/LEI an-WW/W W Patented am. so, was;

earse stares assess ALBERT L. manna, or carver. Fur-iron, omo.

METHOD or EORGING GEAR: wows.

Application filed August 21, 1920. Seria1 N0. 405,074.

The invention relates to amethod of drop 30 forging worms for driving gears. in tractors.

and likemachines, and the object of the improvement is to forge the worms in such a; 'manner that the grain of the metal is formed continuous, and parallel. with 'the surface 3 thereof, and so. that the structure of the. bodyor core of the metal within the worm will'b'e homogeneous throughout,

In machining or forging gear worms by ordinary-'methods,-difliculty is'experienced in cuttin across "or distorting-the grain of the meta with reference'to the surface of the worm and also in .ruptu'ring'or distorting the structure of the metal in the. core or" body of'the worm, with the result of-greatly reducing its efficiency and strength.

These difficultiesare largely avoided by the present process in which the worm is first shaped by one set of forging'dies which;

give the proper spiral pitch to diametrically opposite upper and lower portions of the Worm, While'slightly distorting the pitch of diametrically opposite. lateral the upper and lower portions' only of the partially formed worm.

The improved method forging the Worm thus set forth ingeneral'terms may be. carried out 'by meansof the dies and partial formations, illustrated in the accompanying drawings forming part hereof, in

which Figure 1 is a perspective-view of a blank bar from which the worm is formed;

Fig. 2. a plan viewcf-the shape first given to-the blank;

Fig. 3, a plan view of the preliminary to formation given to-the worm;

V portionsthereof; and then giving the distorted por tions of the worm the correct spiralpitch,- by quarter rotating the partially. formed piece in another set of dies cut to -ac-tfupon Fig. 4:, a side'view of the same showing the distorted side portions of-the worm;

Fig. 5, a side elevation-of the worm after it. is completely formed'with atrue spiral pitch Fig. 6, a

Fig. 7-, an endproject on 0f the same" showing also-the'upper block;

Fig. 8, a section through the upperand" lower blockscontaining preliminary dies on line '8-8,-Figs. (iand 7 -Fig. 9, a plan viewofa block containing the lower dies forjcomp-leting the forging process; and

Fig. 10, a section of an upper, and lowr block containing thecompleting dies, as {on line 10-10, Fig. 9. 1

Similar numerals refer to similar parts throughout the drawings.

.of barl, and the ends of the blank are -pre-ferably first rounded in a-swedging die 2, which 'may be cut in the same block con-- taining the forming die 3 and the preliminary die f; and in the swedgi-ng die, one end of the stock maybed-rawn out to give'material for the guide shank 5.

The stock is then shaped by dies 3 to. give- 1 plan view of alower block .containing the dies" eniployedin the preliminary formations of the worm;

he worm is fOIl-ilfid. from a blank sectionthe outline forms 6 for the worm, .7. and-8 for the bearing ends, and'5 for the. guide 'shankg'at the baseof which shank is formed the shoulder 9 which may constitute the end of the completed- Worm after the guide shank is severed therefrom,

The. worm proper '10 is then shaped around the entire stock by means ofv dies 4;,

which are cut in their middle portionto give the proper form and pitch to corresponding upper and lower portions of the worm; an

are cut. inytheir side portions to give the corresponding 'portions of, the "worm, the proper-section of metal. In'order, however, t'o'glve the dies the necessary clearance draftgthe side portions thereof are shaped to distort the pitch of the side portions of the worm, so that at each. .side the worm is substantially perpendicular to the plane of the face of the dies, as shown in somewhat exaggerated form in Figs. 3 and4.

In the same operation, the dies 4 give the guide stem 5 a square formation, with sides perpendicular to the face of the die, which stem is used as a guide for properly positioning the worm in the subsequent forging which is necessary for giving the worm the proper spiral pitch on all sides.

During the preliminary forging of the worm by dies 4, the stock is positioned therein without any rotating, and after the preliminary shaping of the worm, the fin which may be formed along each side by an excess of metal, is cut off in the usual manner by a trimming press, not shown; and the stock thus trimmed with theworm formed and shaped as shown in Figs. 3 and 4, is then ready for the final forging in dies 11 and 12, which are cut in the same blocks as shown in Figs. -9 and 10.

The finishing dies are shaped to give the final form and pitch in about three-fifths of-the middle portion of the upper and lower sides, as the worm is positioned therein; while the side portions of these dies are cut away so as not to impinge the corresponding portion of the worm, thus limiting the forging action of the finishing dies to about three-fifths of the width of the upper and lower portions of the worm.

The full diameter portions of the worm in the dies 11 and 12 are cut exactly alike, but the end portions are shaped to give the proper taper to the worm when the stock has been rolled a'quarter turn; andeach Worm die is likewise located a correspondingly different distance from the respective off-sets 9 and 9 which'receive the the end shoulders 9 at the base of the guide stem, so that by abutting these ofi-sets by the end shoulder9 as the stock is passed from one die to the other, the worm will have the proper longitudinal position with reference to the respective dies.

In giving the worm the final forging, the a stock is first given one or more blows in die 11, in which it is given a quarter turn from the position in which the preliminary formation was made, which position is made certain by the square of the guide shank,

- and is determined by the eye of the oper- "ator as well as by the squared recess in the block. This quarter turn brings the dis.- torted portions of the worm to the top and bottom of the stock, to be directly acted upon by the middle portions of the dies 11,

which rectify the distorted portions of the worm and give them the true pitch.-

It is evident however, that the proper aligning of the distorted portions of the.

worm will tend to a certain extent to distort the lateral portions of the worm as posltioned in dies 11, because these dies are so cut away that they do not support these upper and lower portions by this die, and

to rectify such distortion the stock is rotat-' ing a quarter turn'back again and given a further forging between dies 11; which rotating operation between dies 11 and 12 is repeated until the entire worm is given its proper pitch, as shown in Fig. 5, thereby completing the forging operation; after which the guide stem may be severed, and the worm is ready for the final heat treatin and machining operations. 4

y the described method of forging the worm, it will be noted that the formation of the worm with a slightly distorted pitch, and the displacement of metal caused thereby, are completed by the preliminary operations in dies 4, and that the resulting grain of the metal in the worm will be substantially parallel the wearing surface thereof;.

and it is evident that the subsequent operation of giving the partially distorted worm its proper pitch by means of dies 11 and 12, the previously formed worm is merely deflected from its distorted position without injuriously affecting the grain of the metal. r

A further advantage of the present improvement, is that the entire process of portion of the worm.

I claim:

1. The method of forging gear worms which consists in first shaping the worm with a distorted pitch and then rectifying the alignment of the same.

2. The method of. forging gear worms which consists in first shapingthe worm with a distorted pitch along diametrically opposite sides, and then rectifying the alignment of the distorted portions.

3. The method of forging gear worms which consists in first shaping the worm with dies which distort the pitch on laterally opposite sides, and then rectifying the pitch by intermittently forging and alternately rotating in other dies acting only upon portions of the worm.

4. The method of forging gear worms which consists in first shaping the worm with dies which distort the pitch on laterally opposite sides and form a guide stem on one end squared to correspond to the distorted portions of the Worm, and then rectifying the pitch by intermittently forging and alternately rotating in other dies act- 5 ing only upon portions during the intermittent forging of the Worm, by reference to the squared guide stem.

5. The method of forging metal gear Worms which consists in first heating the metal and then shaping the Worm with a 10 distorted pitch and rectifying the alignment of the same without-further heating.

ALBERT L. EICHER. 

